Malheureusement, mon moniteur vga brancher à l'aide de cet adaptateur m'affiche le message "no vidéo output" ou devient tout simplement noir.
En effet, les commentaires au sujet de l'alimentation du dongle me semblent pertinents. Le signal VGA étant analogique, le "convertisseur" produisant un signal digital, il doit bien y avoir quelque chose qui alimente le chip qui fait la conversion à l'intérieur du dongle...
Donc, soit celui-ci est alimenté par le HDMI, soit par le VGA, soit de manière externe avec un mini-usb. S'il n'y a pas de mini-usb, l'alimentation doit-être fournie par l'un des deux connecteurs... Normalement, le "device" actif du HDMI devrait fournir 55 mA sous 5V, mais...
An HDMI device that has active electronics should have a provision for external power in order to be compliant (e.g. a receptacle to allow the use of a standard power adapter, sometimes called a power “brick”). Here we are drawing a distinction between “active” devices that actually have some powered electronics, and “passive” devices, such as some switches (more on those later).
Some active devices, such as actively powered HDMI cables or in-line signal extender boxes, will by default attempt to power their electronics by taking power from the 5V line (+5V power) available on the HDMI connector. The HDMI specification requires all source devices to provide at least 55mA (milliamps) on the 5V line for the purpose of reading the EDID of a display. While 55mA is not enough current to operate most HDMI accessory devices (which typically require about 100 to 150mA), most source devices on the market today provide significantly more current on the 5V line than the HDMI specification requires. As a result, the vast majority of accessory devices can operate when interfaced with a source device that provides more than the required current (i.e. over 100-150mA) on the 5V line. However, manufacturers should provide a provision for their powered HDMI accessory devices to obtain external power, and consumers are encouraged to look for this external power provision when purchasing such products.
Looking to the future, not all HDMI devices may provide this much power over the 5V line. For example, as HDMI expands into more and more portable applications (cameras, camcorders, laptops, etc.), power consumption is often much more of an issue, and such devices may not power the 5V line with the > 100mA required by such “active” devices. Again, consumers should consider ensuring that their active HDMI accessory device purchases have a provision for external power for this reason.
Any device which performs processing, amplification, or switching of the HDMI signal should use actively powered electronics to be compliant and perform reliably. As mentioned in the above question, the vast majority of devices can utilize power that is supplied on the 5V line (+5V power) of the HDMI connector to function properly, although we recommend that such devices give the users an optional provision to use an external power adapter. Completely passive, non-powered devices may work in some short-cable length applications, but use them at your own risk, as they may not operate reliably. Even if a passive device works in one configuration, a change in equipment or cabling may introduce failures in subsequent configurations.
J'aurais donc tendance à dire que le dongle n'est pas alimenté, ou qu'il a besoin de trop de courant que ce que peut fournir le HDMI... Ce qu'il fait qu'il ne sort aucun signal VGA du dongle...
dc _______________________________________________ gull mailing list [email protected] http://forum.linux-gull.ch/mailman/listinfo/gull
